This invention relates to metal alloys and more particularly to amorphous metal alloys.
Fe-metalloid amorphous metallic alloy ribbons, when properly annealed in a transverse magnetic field, exhibit extremely high magnetomechanical coupling. These materials are the most strain sensitive materials known, with strain-gauge figures of merit of about 4.times.10.sup.5. Technological exploitation of these materials is made difficult by a number of factors (in addition to the ones inherent in using extremely stress sensitive materials). The ribbons have very high surface-to-volume ratios, greatly exaggerating the importance of surface effects, especially the effect of surface nonuniformity. Another problem is that Fe-metalloid amorphous metallic alloys are extremely prone to corrosion, even in moderately humid air. Conventional protective coating against corrosion place stresses on these materials which render them useless for measuring strains.
Other amorphous metallic alloys (or glassy metals) have desirable properties such as high strength, corrosion resistance, high magnetic permeabilities, etc. Nevertheless these materials are limited in their uses by their high resistivity (about 130 to 160 microohms-cm). Moreover, conventional electroplating can not be used to form metal (e.g., Cu, Ag, Au) coatings on these amorphous metallic alloys. Proprietary methods of electroplating the amorphous metallic alloys appear to be complicated and very expension.
Untika, Inc., of Japan has produced amorphous metallic alloy wires containing chromium which have high strength and resistance to corrosion. Filaments of these amorphous metallic alloys would be useful for reinforcing rubber structures such as tires and sonar domes. Unfortunately, rubber and other elastomers do not bond well to the amorphous metallic alloy filaments.